Biology 9700 · AS & A Level · Natural and artificial selection

Natural and artificial selection — practice question

Selective breeding has been employed to enhance the traits of crop plants, including maize and rice.
(a)[4]

Outline how selective breeding produced vigorous, genetically uniform maize varieties.

(b(i))[1]

Suggest why IR8 is better than the PETA variety of rice.

(b(ii))[1]

Scientists sequenced the DNA of FR13A, IR64 and IR64-Sub1. Suggest the benefit of sequencing the DNA of IR64-Sub1.

(b(iii))[1]

After a few generations of breeding, the scientists crossed IR64-Sub1 with IR64. Explain why the scientists crossed IR64-Sub1 with IR64.

(ii)[1]

Suggest the advantage of sequencing the DNA of IR64-Sub1.

(iii)[1]

Once a few breeding generations had passed, the scientists crossed IR64-Sub1 with IR64. Explain why the scientists crossed IR64-Sub1 with IR64.

(c(i))[4]

With reference to Fig. 6.2, suggest explanations for the different responses to gibberellin shown by dwarf variety A and dwarf variety B.

(c(ii))[2]

BZR1 is a transcription factor involved in controlling growth and development in $A.\ thaliana$. Outline the features of a transcription factor such as BZR1.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: cross plants that have the desired characteristics

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